Articles such as vehicle bodies or vehicle body parts can have a variety of colors and appearance. Surface coatings such as monocoat, colorcoat or basecoat, clearcoat or topcoat, and tricoat are favored for the protection and production of decorative colors. The surface coatings can utilize one or more pigments or effect pigments to impart the desired color or appearance. Accurate and reproducible measurements of colors of the articles are challenging. A number of commercial color systems and devices have been developed for measuring colors and other optical properties of articles, such as surface coatings of the vehicle bodies or body parts. However, there are significant variations in color measurement data among systems or devices. There are still needs for improved method for color measurement.